U.S. patent number 3,667,365 [Application Number 04/809,286] was granted by the patent office on 1972-06-06 for device for compensating positional deviations useful with interchangeable lenses having screw threads.
This patent grant is currently assigned to Kabushiki Kaisha Ricoh. Invention is credited to Sakae Fujimoto, Tadayuki Imai.
United States Patent |
3,667,365 |
Fujimoto , et al. |
June 6, 1972 |
DEVICE FOR COMPENSATING POSITIONAL DEVIATIONS USEFUL WITH
INTERCHANGEABLE LENSES HAVING SCREW THREADS
Abstract
A device for compensating positional deviations in screwing
interchangeable lenses into a single-lens reflex camera by means of
an aperture setting ring including a pin mounted in a slot to
determine its angular movement. A barrel lens has a hook element
engagable with a notched area on the aperture setting ring. The
hook element is mounted to have less angular movement than the
aperture setting ring so that positive engagement is always
provided within the range of movement of the barrel lens.
Inventors: |
Fujimoto; Sakae (Tokyo,
JA), Imai; Tadayuki (Tokyo, JA) |
Assignee: |
Kabushiki Kaisha Ricoh (Tokyo,
JA)
|
Family
ID: |
11996575 |
Appl.
No.: |
04/809,286 |
Filed: |
March 21, 1969 |
Foreign Application Priority Data
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Mar 25, 1968 [JA] |
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43/19337 |
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Current U.S.
Class: |
396/505;
396/529 |
Current CPC
Class: |
G03B
17/14 (20130101); G03B 7/20 (20130101) |
Current International
Class: |
G03B
17/12 (20060101); G03B 17/14 (20060101); G03B
7/20 (20060101); G03b 003/00 () |
Field of
Search: |
;95/44R,64R,64D,1C |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Matthews; Samuel S.
Assistant Examiner: Moses; Richard L.
Claims
We claim:
1. A device for compensating the positional deviations in screwing
interchangeable lenses into a single-lens reflex camera
comprising
a lens mounting;
an aperture setting ring mounted to be rotatable within the lens
mounting to control aperture setting, said setting ring having a
biasing spring connected thereto;
means associated with said setting ring to provide a limited range
of angular movement;
a connection element affixed to said setting ring, said connection
element having an integral notched portions;
each lens being selectively rotatable and mountable within the lens
mounting;
an aperture index cup mounted on one end of said lens and having a
predetermined rotational movement, said predetermined movement
being less than said limited movement of said setting ring; and
a connecting lever extending from said index cup and having a
hook-shaped element at its remote end, said element adapted to
engage said notched portion when said lens is fully threadedly
engaged.
2. A device according to claim 1 in which said means associated
with said setting ring comprises a pin extending from said setting
ring and movable within a notch located in a fixed element within
the camera, said notch determining said limited range of
movement.
3. A device according to claim 1 in which said notched portion
comprises a toothed area, and said hook-shaped element is formed as
a detent ear that is adapted to engage said toothed area.
4. A device according to claim 3 in which said connecting lever is
formed of resilient material to provide elasticity for the
engagement between said toothed portion and said detent ear.
5. A device according to claim 1 in which said hook-shaped element
includes an arm that is rotatable to provide the engagement.
6. A device according to claim 1 in which said notched portion
comprises a stepped portion, a connection ring is rotatably mounted
on said index cup, said connection ring mounted to have a greater
angular movement than said index cup, and the connecting lever is
mounted on said connection ring for engagement with said stepped
portion.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a device for compensating the
positional deviations in screwing lenses into a single lens reflex
camera and more particularly a device for compensating the relative
positional deviations between lenses and the camera body at the
final lens mounting position, which positional deviations differ
from one interchangeable lens to another. In case of a single-lens
reflex camera of the type employing a screw-in lens mounting method
such as "practica mount," a slight positional deviation between a
lens and the camera body at the final lens mounting position will
inevitably occur from one interchangeable lens to another due to
the threaded engagement therebetween. Known in the art is a
mechanism for coupling the diaphragm setting mechanism on the side
of the lens to an automatic aperture setting mechanism on the side
of the camera which coupling mechanism is adapted to couple said
two mechanisms even if there occurs the positional deviation as
described above. However, in the mechanism of the type in which the
rotation of the aperture setting ring on the side of the lens must
be transmitted to the exposure meter for brightness measurement,
the aperture setting ring on the side of the lens cannot be coupled
to the mechanism on the side of the camera without compensating
such positional deviation as described above.
In view of the above, the primary object of the present invention
is to provide a device for compensating such deviation as described
above by providing a connecting element attached to the camera body
or to the lens and a connection element for releasably engaging
with said connecting element which is attached to the lens or to
the camera.
SUMMARY OF THE INVENTION
According to the present invention, the angular range in which an
aperture index cup on the lens can be coupled with an aperture
setting ring on the camera body when the lens is screwed into the
camera or the range of angle of rotation of a connection ring
interposed between said aperture index cup and said aperture
setting ring is made larger than the maximum tolerance in screwing
said lens into said camera.
In one embodiment of the present invention, the connecting element
and the connection element for releasably engaging with the
connecting element are disposed upon the aperture index cup and the
aperture setting ring respectively in opposed relation with each
other, the length of the connection element being extended over a
distance sufficient enough to cover the maximum tolerance in
screwing the lens into the camera.
In another embodiment of the present invention, when the lens is
screwed into the camera body, the connecting element can be
prevented from being in contact with the connection element and can
engage with the connection element only when the lens is positioned
in its final mounting position.
In a further embodiment of the present invention, one connection
ring is fitted over the aperture index cup or aperture setting ring
in frictional engagement therewith. The connecting element is
extending from the aperture index cup while the connection element
of the type described is attached to the aperture setting element,
or vice versa. In this case, the range of angle of rotation of the
connection ring relative to the aperture index cup or the aperture
setting ring is made larger than the maximum tolerance of the type
described above.
According to the present invention, even if the final mounting
position of the lens relative to the camera body is deviated from a
reference position, the aperture index cup can be positively
coupled with the aperture setting ring. Therefore, there can be
provided easily in the camera a device for measuring exposure
brightness at full aperture, and setting automatically the aperture
to a predetermined aperture when the shutter is released for
photography.
The above and other objects, features and advantages of the present
invention will become more clear from the following description
taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS:
FIGS. 1 and 2 illustrate one embodiment of the present invention.
FIG. 1 being a perspective view thereof with a lens being removed
from a lens mount in order to clearly show the components of the
lens and the lens mount while FIG. 2 is a perspective view
illustrating only the lens and its aperture setting ring;
FIG. 3 is a circuit diagram of an exposure meter coupled with the
rotation of the aperture setting ring;
FIG. 4 is a view similar to FIG. 1 but illustrating a second
embodiment of the present invention;
FIG. 5 is an enlarged view of the essential coupling portion
between the aperture setting ring on the camera body and the
aperture index cup on the lens;
FIG. 6 is a perspective view of a third embodiment of the present
invention; and
FIG. 7 is an enlarged view illustrating the coupling portion
between the lens and the camera body shown in FIG. 6.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 and 2 illustrating one embodiment of the
present invention, a lens mount 1 is fixedly secured to the front
surface of a camera body or case. The inner surface of the lens
mount 1 is internally threaded as shown at 1a for threadable
engagement to the externally threaded portion of a lens assembly.
An exposure aperture setting ring 2 is rotatably fitted over the
outer peripheral surface of the lens mount 1 and a spring 3 is
loaded between the camera body and the aperture setting ring 2. A
stopper pin 4 extends from the aperture setting ring 2 for movement
within a slot 5a indicated by chain lines of a stop plate 5 fixedly
attached to the body. A connection plate 6 having a toothed portion
6a is fixedly attached to the aperture setting ring 2 and the
toothed portion 6a has a length larger than the maximum deviation
caused by "screw-in" of the lens system to the camera body. A first
contact element 7 made of a resilient electrically conductive
material is attached to the aperture setting ring 2 through a pair
of insulating members 8 at the base portion of the element 7. The
base portion of a second contact element 9 also made of a resilient
electrically conductive material is electrically connected to the
aperture setting ring 2 in an opposed relation with the first
contact element 7. A resistor ring 10 having a toothed portion 10a
formed at one portion of its outer periphery is rotatably attached
coaxially of the lens mount 1. A semi-circular sliding resistor
plate 11 is attached to the front surface of the resistor ring 10
in electrical contact with the leading end of the first contact
element. The leading end of the second contact element 9 which
functions as a ground connection, contacts a further semi-circular
front surface of resistor ring 10 which is adjacent to sliding
resistor 11. Intermediate gears 12 and 13 are assembled in unitary
construction and the intermediate gear 12 is in mesh with the
toothed portion 10a of the resistor ring 10. The intermediate gear
13 is in mesh with a shutter speed selection gear 14 to which is
coaxially releasably attached a film sensitivity selection gear 15,
whereby when the shutter speed or film sensitivity setting is
varied, the resistor ring 10 is caused to rotate.
A detent connection lever 18 made of a resilient material extends
from an exposure aperture index cap 17 rotatably fitted over a lens
barrel 16 and has a detent ear 18a at the free end thereof. This
detent ear 18a is adapted to engage with teeth of the toothed
portion 6a of the connection plate 6 attached upon the aperture
setting ring 2 on the camera body when the lens barrel 16 is
threadably engaged with the lens mount 1.
The configurations of the connecting lever 18 and the connection
plate 6 and the elasticity of the connection lever 18 are so
determined that the force for connecting or coupling the connection
lever 18 and the connection plate 6 becomes greater than the total
of the force acting between the spring 3 and the first contact
element 7 and the friction force between the second contact element
9 and the resistor ring 10 and that the engagement between the
detent ear 18a and the teeth 6a is released in either direction
when an appropriate external force is applied. The angle of
rotation of the aperture setting ring 2 whose rotation is limited
by the stopper pin 4 and the notch 5a is larger than the maximum
angle of rotation of the aperture index cup 17 of an
interchangeable lens. Furthermore, the angle of rotation of the
aperture setting ring 2 corresponding to the angle of rotation from
one stop to another of the aperture index cup 17 is made equal to
that of the resistor ring 10 corresponding to one stop or step
movement of the shutter speed setting means or film sensitivity
setting means. Moreover, the resistance of the sliding resistor
plate 11 is so suitably selected that the pointer of a meter in the
meter circuit shown in FIG. 3 rotates through one LV graduated
scale in response to the above one unit of angle of rotation (that
is the angle of rotation from one stop to another or from one index
mark to another).
Prior to the attachment of the interchangeable lens, the aperture
setting ring 2 is positioned in the minimum aperture position for
each of the interchangeable lenses as shown in FIG. 2 since the
stopper pin 4 is in contact with one edge of the notch 5a of the
stationary stopper plate 5. When the lens 16 is threadably engaged
with the lens mount 1 by rotating the lens 16 in the clockwise
direction against the coupling force between the connection lever
18 and the connection plate 6 to the attachment position (where the
lens 16 is held securely in position) and when the aperture index
cup 17 is rotated to its maximum aperture position, the detent ear
18a of the connection lever 18 engages with the teeth of the
toothed portion 6a of the connection plate 6. When the exposure
aperture index cup 17 is rotated from this state, the connection
lever 18 is caused to rotate in unison with the aperture setting
ring 2 against the spring 3 so that the first contact 7 slides over
the sliding resistor plate 11, thereby varying the resistance of
the meter circuit shown in FIG. 3 and consequently the pointer
indication thereof. As described above, the angle of rotation of
the aperture setting ring 2 is made larger than the maximum angle
of rotation of the aperture index cup 17 so that the aperture
setting ring 2 can be drivingly coupled with the aperture index cup
17 wherever the cup 17 is positioned or set. When the film
sensitivity or shutter speed setting is varied while the aperture
setting remains unchanged, the resistor ring 10 is caused to rotate
while the position of the first contact element 7 remains
unchanged, thereby varying the resistance of the meter circuit as
in the case of the aperture setting. To remove the lens 16, it may
be rotated in the counterclockwise direction against the coupling
force between the lever 18 and the connection plate 6.
So far the connection plate 6 has been shown as being attached to
the aperture setting ring 2, but it may be attached to the aperture
index cup 17 while the connection lever 18 may be attached to the
aperture setting ring 2, thus resulting in the same effect.
Another embodiment of the present invention will be described
hereinafter with reference to FIGS. 4 and 5. A bearing 19 is
attached to the lens aperture index cup 17 for supporting a shaft
20 which in turn carries rotatably a connection member 21. A spring
22 extends between the aperture index cup 17 and the connection
member 21 so that the detent ear 21a of the connection member 21
normally engages with the toothed portion 6a. An upright arm 21b is
formed integral with the connection member 21 and is adapted to be
rotated in the direction indicated by the arrow through an angle of
about 90.degree., thereby holding the connection member 21 in
position through a suitable locking means not shown. Other
constructions are similar to those of the first embodiment. The
interchangeable lens 16 may be attached in this state and the arm
21b is raised to the position shown in FIG. 5 by releasing the arm
21b from the locking means at the attachment position of the lens
16 thereby engaging the connection member 21 with the toothed
portion 6a. The toothed portion 6a may be formed in the aperture
index ring 17 while the connection member 21 is attached to the
aperture setting ring 2.
Next a third embodiment of the present invention will be described
with reference to FIGS. 6 and 7. A connection ring 24 is rotatably
fitted over the aperture index cup 17 in frictional engagement
therewith through a spring 23. The range of angle of rotation of
the connection ring 24 relative to the aperture index cup 17 is
made larger than the maximum tolerance of the threading or screwing
rotation of the lens 16. A connection member 25 made of a resilient
material extends from the connection ring 24. A stepped portion 26
for receiving the connection member 25 is formed in the periphery
of the aperture setting ring 2 at such a position that whenever
interchangeable lens 16 is set to its minimum exposure aperture,
its connection member 25 always extends from the connection ring 24
over the stepped portion 26. Thus, when the lens 16 is rotated in
the clockwise direction in FIG. 6, the detent ear 25a engages with
the stepped portion 26 while when it is rotated in the
counterclockwise direction, this engagement may be released by
applying a suitable force. With this arrangement and construction,
when the lens is attached by rotating the lens in the clockwise
direction in the lens mount, the rotation of the connection ring 24
is stopped when the connection member 25 engages with the stepped
portion 26 and, thereafter, only the aperture index cup 17 is
rotated against the spring 23 together with the lens 16, thereby
threadably engaging the lens 16 with the lens mount.
When the aperture index cup 17 is rotated in the counterclockwise
direction in FIG. 6, the connection ring 24 is rotated against the
spring 23 so that the aperture setting ring 2 coupled therewith
through the connection member 25 is caused to rotate against the
spring 3.
In the third embodiment described hereinabove, instead of coupling
the aperture index cup 17 in frictional engagement with the
connection ring 24, the connection ring 24 may be fitted over the
aperture setting ring 2 in frictional engagement therewith while a
connection member may extend from the aperture index cup 17 the
member for receiving this connection member may be provided in the
connection ring 24 as in the case of the first and second
embodiments. Furthermore, the connection between the aperture
setting ring and the aperture index cup may be effected by
utilizing other locking devices such as click-ball, click-pin or
the like.
As described in detail hereinabove, according to the present
invention, the range of engagement between the connection member
and the connection member receiving portion, that is toothed
portion or the stepped portion or the angle of rotation of the
connection ring is made larger than the maximum tolerance in
threading the interchangeable lens into the lens mount, thereby
compensating this tolerance. Especially in the construction of the
second embodiment of the present invention, the lens or lens barrel
can be rotated in such a manner that the above described connection
member will not contact with the connection member receiving
member, that is the toothed portion, whereby neither friction nor
noise will be generated upon attachment or removal of the
interchangeable lenses. Furthermore, in the third embodiment of the
present invention in which the connection ring is fitted over the
aperture setting ring or aperture index cup in frictional
engagement therewith in such a manner that the angle of rotation of
the connection ring relative to the aperture setting ring or
aperture index cup is made larger than the maximum tolerance in
screwing the interchangeable lens into the lens mount for
attachment, neither friction nor noise will be generated and the
manual operation for engaging or releasing the connection lever
will not be required, resulting in easy and simple
manipulation.
It will be clear that when the method and device of the present
invention described hereinabove are applied to the TTL type
single-lens reflex camera, the rotation of the aperture index cup
on the interchangeable lens may be transmitted to the member fitted
on the camera body by an extremely simple mechanism, thereby
permitting the measurement of light brightness at full aperture
which has been so far impossible in the camera of the type
described.
* * * * *